EventBase keepAlive counter is not atomic
Summary: Since loopKeepAlive() is always used from the EventBase thread, there's no need for the overhead of an shared_ptr (and therefore, an atomic ref counter); we can get away without thread safety. This also allows us to discard the (sometimes incorrect) optimization of not returning a handle when it appears the loop will continue running anyways
Reviewed By: andriigrynenko
Differential Revision:
D3375503
fbshipit-source-id:
474e4fcf992bdc4fcca9370d3c57bdcc4e042386